Adding 3 months to the output of the "date" command

[Tommy_6]

Hi everyone,
I am running the date command with the folling options:

date "+%Y%m%d%I%M%S"

How would I generate today date in this format with 3 months added to it.

Thanks is advance!!!

Tommy

[Jeroen Peereboom]

I've seen many questions on dates, all seem to be answered by something called 'caljd'. Search the forum (top of the page) for caljd.

JP.

[Steven E. Protter]

http://www.hpux.ws/merijn/caljd-2.3.sh

http://www.hpux.ws/merijn/caljd-2.2.pl

SEP

[Fred Ruffet]

Using perl...

/opt/perl/bin/perl
use Time::Local 'timelocal_nocheck';
($sec,$min,$hour,$mday,$mon,$year,$wday,$yday) = localtime(time);
print scalar localtime timelocal_nocheck $sec,$min,$hour,$mday,$mon+3,$year;
print "\n";

[Hein van den Heuvel · Accepted solution]

Well, with perl (as much as I like that), you would have to putz around with correcting the y/m base to get the right desired numeric output (add 1900 and such).

Given this specific request with the numeric input, and just adding monts, not days the calendar math becomes trivial. extract the month, add 3, overflow at 12 into the year.

For example in awk:

$ cat x
{
y=substr($0,1,4);
m=substr($0,5,2)+3;
if (m>12) { m=m%12; y++ };
x=substr($0,7,99);
printf("%d%02d%s\n",y,m,x);
}
$ date "+%Y%m%d%I%M%S" | awk -f x
20040708015008
$
$ date "+%Y%m%d%I%M%S"
20040408015013


just for grins!
Hein.

[Francisco J. Soler]

Hi Tommy, if you download the gnu date, you can do this very easily:

date --date '3 months' +%Y%m%d%I%M%S

Frank.

P.S. You can get this date version from:
http://hpux.cs.utah.edu/hppd/hpux/Gnu/coreutils-5.2.0/

[Hein van den Heuvel]

btw... you need to define '3 months' more sharply.

When adding 3 months to Jan-31, do you want it to become Apr-30 or May-1, because Apr-31 does not exist (but my hack will output just that!) Ditto for Nov-29 & 30.
Does you perhaps want to add 13 weeks?
Or do you know this will be run on the first of the month?

Just thought I'd warn you...

Hein